Try installing some other game from the store and make sure that works. Also try searching for the HW2 bundle and clicking through to HW1 DE from there.So, I got my code yesterday. I've redeemed it. But I can't find a way to actually bloody install the thing on my PC!
There's two entries for the game on the Windows 10 store, one says the game's not currently available, and the other says I own the product but offers no download button!
There are two store entries so I don't know what if anything you're doing wrong. Oh yeah this is good advice:
On the store click the icon top right > My > Library > Games - Show All > Find and install?
Look through your library. I think it helped me.